In the rearing of animals, such as companion animals and livestock, ectoparasites cause enormous losses, including economic losses, particularly because many ectoparasites can act as disease vectors.
The control of animal ectoparasites is an ongoing challenge. For example, numerous strains of ticks have developed resistance to a wide range of pesticides such as arsenic, hexachlorohexane, camphechlor, DDT, pyrethrines, carbamates and organophosphorous compounds despite the fact that these compounds have varied modes of action and several distinct primary sites of attack in the ectoparasite. It is therefore generally accepted that it is highly desirable to develop and commercialize additional active agents with new modes of action for ectoparasite control.
Compounds harboring a quinazoline, pyrazole or pyrimidine core are well known for their fungicidal, insecticidal and miticidal use in the crop chemistry applications (e.g., U.S. Pat. No. 5,411,963). However several reports have indicated that fenazaquin and tebufenpyrad have limited spectrum of activity against insect pests as well as relatively low toxicity to beneficial mite species under normal use (Pest Manag Sci 2005 61(2):103-10).